【摘要】：隨著大量寒區(qū)巖土工程、人工凍結(jié)工程的進(jìn)行,受到周期性低溫作用或長(zhǎng)期處于低溫凍結(jié)狀態(tài)的寒區(qū)圍巖,其力學(xué)特性與常溫狀態(tài)的差別越來(lái)越引起人們的重視,為保證寒區(qū)工程的安全性,深入研究?jī)鼋Y(jié)巖石的力學(xué)性質(zhì)顯的越來(lái)越重要。以鞍山地區(qū)的礦體主要圍巖—混合巖為研究對(duì)象,對(duì)飽水和干燥兩種混合巖試樣,進(jìn)行了系統(tǒng)的單軸、三軸壓縮試驗(yàn),研究分析了凍結(jié)溫度、圍壓對(duì)飽水和干燥兩種含水狀態(tài)混合巖的變形與強(qiáng)度特性的影響。論文主要研究結(jié)果如下:(1)三軸試驗(yàn)中,隨著圍壓的上升混合巖軸向峰值應(yīng)力呈線性增長(zhǎng)趨勢(shì)。當(dāng)溫度條件為常溫時(shí),圍壓從0MPa增至6MPa試樣的軸向峰值應(yīng)力增長(zhǎng)130%,溫度條件為-5℃時(shí),增長(zhǎng)129%,溫度為-20℃時(shí)增長(zhǎng)155%;在溫度降低過程中,兩種狀態(tài)混合巖試樣的彈性模量都以拋物線規(guī)律增長(zhǎng),飽水試樣的彈性模量增大程度更明顯,而泊松比隨試驗(yàn)溫度的降低而不斷減小但總體變化幅度較小;混合巖粘聚力隨溫度的降低線性增大;內(nèi)摩擦角隨溫度降低略有增大。(2)飽水狀態(tài)和干燥狀態(tài)兩種混合巖的軸向峰值應(yīng)力均隨溫度的降低而增大且成一定的規(guī)律;飽水混合巖對(duì)溫度更敏感,在溫度降低過程中,軸向峰值應(yīng)力增長(zhǎng)更快。不論單軸還是三軸試驗(yàn),飽水混合巖峰值應(yīng)力要大于干燥混合巖,且在零下溫度環(huán)境中,飽水混合巖強(qiáng)度要遠(yuǎn)大于常溫條件混合巖強(qiáng)度。(3)在破壞特性方面,單軸壓縮試驗(yàn)中混合巖試樣破壞形式是與軸向近似平行的劈裂破壞;三軸壓縮試驗(yàn)中主要為剪切破壞,圍壓較低時(shí),基本上呈宏觀單一斷面的剪切破壞,且破裂面隨溫度的降低而越發(fā)平滑。
[Abstract]:With the development of a large number of geotechnical engineering and artificial freezing engineering in cold region, people pay more and more attention to the difference between mechanical properties and normal temperature state of surrounding rock in cold region, which is subjected to periodic low temperature action or long-term low temperature freezing state. In order to ensure the safety of cold zone engineering, it is more and more important to study the mechanical properties of frozen rock. Taking the main surrounding rock and mixed rock in Anshan area as the research object, the uniaxial and triaxial compression tests of saturated and dry mixed rock samples were carried out, and the freezing temperature was analyzed. The influence of confining pressure on deformation and strength characteristics of saturated and dry mixed rocks. The main results are as follows: (1) the axial peak stress of mixed rock increases linearly with the increase of confining pressure in triaxial test. When the temperature is normal, the axial peak stress of the specimen from 0MPa to 6MPa increases by 130, when the temperature is -5 鈩，

本文編號(hào)：2382289